The Water Tech Corp PBW022SS Pool Blaster Max Sand and Silt Filter Bag is for use with the Pool Blaster Max, and it is designed to catch smaller and fine debris such as sand, silt, etc. It is not recommended to be used with leaves and larger debris. It works similar to the All Purpose Filter. It is located inside the Max funnel and is locked in place with the Max Nose cap. Debris will be caught by the SS filter and will keep debris from contact with the impeller/motor. This filter can be emptied, cleaned, and/or replaced. This is needed if the consumer is cleaning a pool containing small, fine debris.